The Prevention

Avoid the Heat Air quality is lowest when the temperature is highest. Plan outdoor physical activity for morning or evening.

Go Off-RoadAvoid walking or biking along busy streets, where levels of pollutants tend to be higher.

Stay LevelheadedGo to airnow.gov to check the EPA's daily air quality forecast for more than 300 cities.

Shield Yourself Home air filters can block particulate matter. Make sure yours rate 9 or higher on the MERV scale (the industry standard for filter efficiency). When sitting in traffic, use the recycled-air setting on your A/C so you don't suck in fumes.

Listen to Your BodyIf you're exercising outside on a smoggy day and you feel tightness in your chest, or if your eyes are teary, itchy, or red, "don't push it," Edelman says.

Eat Clean Cuisine Stock up on foods high in antioxidants, like cherries, kale, and tomatoes. Antioxidants trap free radicals, which help pollutants do their dirty work in the body.